1. Field of the Invention
The present invention relates to a liquid application apparatus and method, and to an image forming apparatus, and more particularly to a liquid application apparatus and method having a composition in which liquid is supplied onto the surface of a round cylindrical member, such as a gravure roller, and to an image forming apparatus having a composition in which treatment liquid (undercoating liquid) is applied using this liquid application apparatus and method.
2. Description of the Related Art
Japanese Patent Application Publication No. 4-64488 discloses technology for stabilizing an application process by separating a doctor blade from a gravure roller (also referred to as a “gravure cylinder”) to remove the remaining application liquid left between the doctor blade and the gravure roller by means of a fluid, each time application is performed on a substrate.
Japanese Patent Application Publication No. 10-230201 discloses technology for preventing an application liquid from drying out and becoming affixed to the surface of an application roller, by separating a pressing roller (also referred to as an “impression roller”) and application liquid tank, when application liquid is not being applied onto a receiving body.
Japanese Patent Application Publication No. 2001-166448 discloses technology for reducing image application non-uniformities by leveling a sprayed treatment liquid by means of a roller, a blade, or an air flow.
Japanese Patent Application Publication No. 2006-95489 discloses technology for achieving application of an ultra-thin layer having a film thickness of not greater than 10 μm, by reverse rotation application using a gravure roller, and it also discloses technology for curing an applied film by irradiating ultraviolet light while supplying an inert gas.
In the invention described in Japanese Patent Application Publication No. 4-64488, although it is possible to stabilize application by removing remaining liquid by means of air or liquid, it is not suitable for high-speed processing since the doctor blade needs to be separated from the gravure roller frequently. Furthermore, it is also difficult to control application in the conveyance direction and the breadthways direction.
In the invention disclosed in Japanese Patent Application Publication No. 10-230201, although it is possible to reduce affixation onto the roller surface, there is a problem in that application non-uniformities are liable to occur due to the effects of residual fixed material. Furthermore, when the application liquid in the application liquid tank is separated, then it is possible to control application in the conveyance direction, but liquid trails are liable to occur and the response is not satisfactory.
In the invention disclosed in Japanese Patent Application Publication No. 2001-166448, although it is possible to simplify the application of the liquid by means of the spraying of treatment liquid from nozzles, during rotation of the roller in the forward direction, or pressing of the blade, non-uniformities such as stripe-shaped non-uniformities are liable to occur, and the treatment liquid that has dried and solidified is liable to become attached to the roller or blade. Moreover, non-uniformities are liable to occur in the breadthways direction due to air blowing, and it is difficult to control the application thickness by means of air blowing.
In the invention disclosed in Japanese Patent Application Publication No. 2006-95489, the treatment liquid which has dried and solidified is liable to become attached to the roller, and even when application has been halted, liquid trails are liable to occur and therefore the control characteristics cannot be regarded as satisfactory.
Moreover, in the field of inkjet recording, intermediate transfer methods have been investigated in the related art, with the object of achieving good image formation onto media of various types, and it has been found that, in particular, a method which applies an undercoating liquid (treatment liquid) such as an ink aggregation agent, to an intermediate transfer body is suitable for forming images. When an image is formed on a cut paper by means of this method, then although good reverse rotation application is achieved on the gravure roller, which enables good film thickness uniformity when applying the undercoating liquid (see Japanese Patent Application Publication No. 2006-95489), it is difficult to control the application range and there are cases where the undercoating liquid adhering to portions outside the paper becomes attached to the transfer roller, and the intermediate transfer body becomes soiled by retransfer of this liquid. Furthermore, in cases where the undercoating liquid is acidic, then corrosion of the structural members, such as the transfer roller, may be caused by the liquid. Moreover, in cases where liquid has been attached to the gravure roller for a long period of time also, there is a possibility of drying solidification or damage resulting from corrosion.